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Switch Help

6 messages · oscar linares, Colin Millar, Henrique Dallazuanna +1 more

Colin Millar
# 
I think you just missed some commas out...  

aar <-
function(command = c("scrn", "dx", "df"))
{
  command <- match.arg(command)
  switch(command,
    scrn = cat("scrn  :Screening","\n"),
    dx   = cat("dx    :Diagnosis","\n"),
    df   = cat("df    :Don't Forget","\n")
  )
}

Colin.


Ps you don't need the curly brackets here if theres only one expresion,
and sometimes its good to restrict the inputs to only those you want
So that

aar("something wrong")

# Error in match.arg(command) : 'arg' should be one of "scrn", "dx",
"df"


-----Original Message-----
From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-project.org]
On Behalf Of oscar linares
Sent: 18 November 2009 10:40
To: r-help at r-project.org
Subject: [R] Switch Help

Dear Rexperts,

Given,

aar <-function(command) {

switch(command,
  {scrn = cat("scrn  :Screening","\n")}
  {dx   = cat("dx    :Diagnosis","\n")}
  {df   = cat("df    :Don't Forget","\n")}
)
}

I want to be able to do:

aar("dx") # function does cat("dx    :Diagnosis","\n")

aar(c("dx","df"))  # function does cat("dx    :Diagnosis","\n")
                        # function does df   = cat("df    :Don't
Forget","\n")

BUT IT IS NOT WORKING FOR ME.

Please help:-)
Colin Millar
# 
And if you want to do both do

invisible( lapply(c("scrn","dx"), aar) )

but I think you will have to use multiple ifs rather than switch if you
intend to add more functionality...


.
.
.

I think you just missed some commas out...  

aar <-
function(command = c("scrn", "dx", "df")) {
  command <- match.arg(command)
  switch(command,
    scrn = cat("scrn  :Screening","\n"),
    dx   = cat("dx    :Diagnosis","\n"),
    df   = cat("df    :Don't Forget","\n")
  )
}

Colin.


Ps you don't need the curly brackets here if theres only one expresion,
and sometimes its good to restrict the inputs to only those you want So
that

aar("something wrong")

# Error in match.arg(command) : 'arg' should be one of "scrn", "dx",
"df"


-----Original Message-----
From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-project.org]
On Behalf Of oscar linares
Sent: 18 November 2009 10:40
To: r-help at r-project.org
Subject: [R] Switch Help

Dear Rexperts,

Given,

aar <-function(command) {

switch(command,
  {scrn = cat("scrn  :Screening","\n")}
  {dx   = cat("dx    :Diagnosis","\n")}
  {df   = cat("df    :Don't Forget","\n")}
)
}

I want to be able to do:

aar("dx") # function does cat("dx    :Diagnosis","\n")

aar(c("dx","df"))  # function does cat("dx    :Diagnosis","\n")
                        # function does df   = cat("df    :Don't
Forget","\n")

BUT IT IS NOT WORKING FOR ME.

Please help:-)
Henrique Dallazuanna
# 
If you want type twice commands in function aar, you could try this:

aar <-function(command) {
	switch(command,
	 scrn = cat("scrn  :Screening","\n"),
	 dx = cat("dx    :Diagnosis","\n"),
	 df = cat("df    :Don't Forget","\n"))
}

invisible(Vectorize(aar)(c('dx', 'df')))
On Wed, Nov 18, 2009 at 8:39 AM, oscar linares <winsaam at gmail.com> wrote:

  
    

      
      
    

  


  


      

    

    

      
      

        


  

        

      Alain Guillet
    

    

      
      #
    

  


  

      
I believe that is what you want:

aar <-function(command) {
    for(i in command){
        cat(i,":",switch(EXPR=i,
             scrn = "Screening",
             dx = "Diagnosis",
             df = "Don't Forget"),
        "\n")
    }
}

 > aar(c("dx","df"))
dx : Diagnosis
df : Don't Forget


Alain

        
oscar linares wrote: